This invention relates to instruction indicating apparatus and, more particularly, to such apparatus which is adapted for use in a recording/playback system so as to provide a display of particular information, such as instructions, which is recorded on a movable record medium, and wherein the apparatus is fully electronic.
In many recording/playback devices wherein information is recorded on and/or played back from a record medium, such as a magnetic tape, a magnetic sheet, a disc, or the like, it often is desirable to provide indications of the locations of particular information on that record medium. For example, in dictating equipment, a user may record various instructions at particular locations of the record medium. In transcribing the dictated information, it is advantageous to provide the transcriptionist with indications of the locations whereat the particular instructions are recorded so as to facilitate the preparation and transcription of that information. Accordingly, in prior art dictation equipment, the locations of such instructions are provided by marking an indicating slip, such as an index scale which is marked by a pencil, a solenoid-activated scribing instrument, a heater element, or the like. Of course, the marked indicating slip usually originates at the dictator's apparatus and, therefore, must accompany the record medium to the transcriber's apparatus in order to be properly used. Hence, there is the possibility that the marked index scale will be lost or otherwise separated from the record medium.
In a central dictation system wherein each of a plurality of remotely situated dictators may dictate information onto a centrally disposed record medium, particular signals representing the end of dictation of a particular dictator may be generated. It is desirable to display the relative locations of these end-of-dictation signals so as to apprise the transcriptionist of the length of a particular piece of dictation which is being transcribed. In such a central dictation system, the use of marked index scales of the type described above is not practical.
Furthermore, when digital data is recorded on a record medium, various blocks of data may be identified by recording corresponding identifying signals relating to the type, length, composition or other characteristics of that data. It is advantageous to provide indications of such identifying signals so as to facilitate a rapid selection and access of a desired block of data.
It has heretofore been proposed to record predetermined identifying signals on the record medium during a recording operation so as to identify the location and type of data associated with such signals. In the environment of a dictation system, these recorded signals are instruction signals which serve to locate a position of an associated instruction. As described in U.S. Pat. No. 3,040,135, these recorded instruction signals are tone signals which are not audibly sensed during a playback operation. In preparation of a transcribing operation, the record medium is rapidly scanned to detect the presence of these tone signals and to mark an index strip which is scanned in synchronism with the scanning of the record medium. Unfortunately, if the record medium is a magnetic tape cassette, a magnetic belt, a magnetic disc, or other discrete media, a separate index slip is needed for each medium. Either time-consuming, and often frustrating, operations must be performed to suitably load the index slip in an appropriate marking mechanism for each record medium, or complex and costly automatic devices must be provided for this purpose. In addition, the use of such index slips is not readily desirable in the environment of a central dictation system.
The foregoing problems associated with the marking of index slips generally are overcome in accordance with the apparatus disclosed in U.S. Pat. No. 4,051,540, assigned to the assignee of the present invention. In this apparatus, rather than using an index slip, a series of light sources, such as light emitting diodes (LED's) are selectively energized to provide indications of the locations whereat instruction signals are recorded. In preparation for a transcribing operation, the record medium, which may be a magnetic tape cassette, is scanned to detect the locations of recorded instruction signals, or tones. Synchronized with this scanning of the magnetic tape, a wiper element scans successive LED's. Accordingly, the one LED which is contacted by the wiper element at the time that an instruction tone signal is reproduced is energized. At the completion of the scanning operation, the selective energization of the LED's provides a visual indication as to the locations of recorded instruction signals. Furthermore, and in order to reference the energized LED's to an index scale, a slidable index, previously marked in time gradations, is advanced as the record medium is scanned. At the conclusion of this scanning operation, not only are the LED's properly energized, but the index scale provides a close approximation of the overall length of recorded information. Thus, by referencing the energized LED's to this index scale, the relative locations of recorded instruction signals are ascertained.
Although the just-described instruction indicating apparatus functions satisfactorily, this apparatus utilizes a mechanical assembly to scan the LED's and to display the index scale. Such a mechanical assembly adds to the overall cost of construction to the system with which the indicating apparatus is used. Furthermore, in that apparatus, a constant zero reference position for the index scale is not provided. Rather, a so-called "floating zero" is used, this floating zero being dependent upon the overall length of dictated information. It is believed that a user would prefer a fixed, left-margin zero point for the index scale. Still further, the versatility of the instruction indicating apparatus of the aforedescribed type is relatively limited. That is, it generally is capable only of providing indications of the locations of instructions which are recorded on the record medium. It is advantageous if various types of instructions can be identified, and the locations of such different types of instructions be displayed.